Faucet Aerators and hot water supply

JJ_4

This is slimly related to heating...but I have a problem in one of our buildings that I think may be related to the install of low flow aerators on all of the restroom faucets.

This is a 3 story building. It has a pumped system (though I don't think it is recirculating...need to look at the mechancials) with a mixing controller in the 1st floor boiler room.

We have been getting complains of lack of hot water at the faucets on the 3rd floor..and some on the 2nd (though fewer). The pump is fine and has been checked out. This (the complaints) started shortly after we installed low flow aerators.

Could this problem be caused by the aerators? I found a couple of places on the web that suggest this, but thought I'd ask some pros.

Thanks,

MikeyB

aerators

JJ, are they the 0.5 gpm aerators? we installed them as well, and we have a hw re-circ, it does take a while for the hot water to get to your hands, plus we have Chicago metering faucets that dont help much, the new aeraotrs cut the flow way back. I know of other bldgs that are having the same problem

JJ_4

.5 gpm with recirc.

Yes they are .5 gpm and I checke the mechanicals...we have recirculation. So you are saying you have heard about this from several people?

Thanks for the info.

GMcD

Low flow aerators

It's not so much the aerators, it's a "system" issue. The plumbing codes and design standards haven't caught up to the low flow faucets yet. Unless the DHW recirc line is connected closer to the faucet, you will have a "dead leg" of hot water pipe. Say it's a 20 foot length of 1/2" pipe from where the recirc pipe connection is made, and it will contain about 0.8 gallons. The first time someone turns on the tap it will take about 0.8/0.5 = 1.6 minutes, or more to get hot water to the tap. The longer the pipe, and the bigger the pipe feeding the faucet, the longer it will take hot water to get there.

The green buildings world is learning about this- there are many brand new green/LEED buildings with poor hot water delivery due to the extensive use of low flow fixtures and using "standard" recirc and DHW heat maintenance design. My own standard is to design the piping to have no more than a 10 second wait time for hot water, and that can be accomplished by either taking off the DHW recirc connection within 3 feet (1M) of the faucet, or use some HWAT electrical heat maintenance cable wrapped on the DHW pipe to within 3 feet (1M) of the faucet.

The problem that retro-fitting older systems with new low fixtures at sinks is that more water ends up being used and wasted while people wait longer for hot water at the tap. So tell me again how much water we are saving with retro-fitting low flow faucets again?

Bigugh_5

Exactly liike!

our ecomony.
Think about it! is not the $$$ mess we are in the same thing. No hot water we can use, but plenty avaliable. So build a bigger water heater, put in a bigger pump, and the slow flow will still be slow and there will still be complaints. We have got to fix the piping to do away with the slow flow some how. how about we do away with the Areators, (government) and see if that works. Reagan said it "Government is the problem" the Gov. has given away the piping to foreign folks! so they cannot fix that!